1. Field of the Invention
The present invention is in the field of access doors intended to be used on air conditioning (heating and cooling) ducting to permit elements within the ducting system, such as air turning vanes and the like to be accessed from time to time.
2. The Prior Art
In air conduit systems such as are used for heating and cooling it is often necessary to provide means for obtaining access to components disposed within the ducting. One conventional mode of providing such access involves supplying a frame to which a door is hinged. The door and frame, comprising a unitary assembly, may include gasketting material for preventing leaks at the duct interface and a latch whereby the door may be released from the closed condition to an open condition.
Composite assemblies of the type described are mounted by cutting an appropriately sized hole in the duct and by affixing flanges formed on the frame component to exterior surfaces of the duct, as by a multiplicity of sheet metal screws or the like.
Assemblies of the type described are relatively expensive and time consuming to install.
Other forms of access door mechanisms for ducts, etc. are illustrated in one or more of the following U.S. Pat. Nos: 1,849,907; 3,537,212; 4,206,784; 3,566,566; 4,890,418.
The assemblies of each of the door devices described are relatively complex and necessitate substantial metal work to effect installation.